Experimental Observation of Proton Bunch Modulation in a Plasma at Varying Plasma Densities.

We give direct experimental evidence for the observation of the full transverse self-modulation of a long, relativistic proton bunch propagating through a dense plasma. The bunch exits the plasma with a periodic density modulation resulting from radial wakefield effects. We show that the modulation is seeded by a relativistic ionization front created using an intense laser pulse copropagating with the proton bunch. The modulation extends over the length of the proton bunch following the seed point. By varying the plasma density over one order of magnitude, we show that the modulation frequency scales with the expected dependence on the plasma density, i.e., it is equal to the plasma frequency, as expected from theory.

Experimental Observation of Plasma Wakefield Growth Driven by the Seeded Self-Modulation of a Proton Bunch.

We measure the effects of transverse wakefields driven by a relativistic proton bunch in plasma with densities of 2.1×10^{14} and 7.7×10^{14} electrons/cm^{3}. We show that these wakefields periodically defocus the proton bunch itself, consistently with the development of the seeded self-modulation process. We show that the defocusing increases both along the bunch and along the plasma by using time resolved and time-integrated measurements of the proton bunch transverse distribution. We evaluate the transverse wakefield amplitudes and show that they exceed their seed value (<15 MV/m) and reach over 300 MV/m. All these results confirm the development of the seeded self-modulation process, a necessary condition for external injection of low energy and acceleration of electrons to multi-GeV energy levels.

Nanostructured lipid carriers loaded with curcuminoids: Physicochemical characterization, in vitro release, ex vivo skin penetration, stability and antioxidant activity.

Four formulations of nanostructured lipid carriers (NLC) loaded with curcuminoids where prepared, testing two types of solid lipids (Compritol® 888 ATO and Precirol® ATO 5) and two kinds of stabilizers (poloxamer 407 and polysorbate 80). Particle size values between 111 and 214 nm and polydispersity indices < 0.3 were registered, with low Z potential values due to the nonionic character of the stabilizers. The results showed that the type of surfactant had an impact on the in vitro release rate and on the ex vivo skin permeation capability of curcuminoids. Polysorbate 80 delayed the release, but favors the transport of a higher amount of curcuminoids to the receptor solution during the ex vivo permeation studies than the systems with poloxamer 407. Confocal microscopy confirmed that all systems favored the penetration of curcuminoids to deeper layers of the skin and in a greater amount than curcuminoids in solution. Exposure of the systems to intense radiation caused the degradation of curcuminoids, without loss of antioxidant activity, confirming that the degradation products also function as antioxidants. The NLC prepared can be valuable carriers to enhance the penetration of curcuminoids into the skin, to treat different disorders and skin diseases.

Role of neuronal voltage-gated K(+) channels in the modulation of the nitrergic neurotransmission of the pig urinary bladder neck.

BACKGROUND AND PURPOSE: As nitric oxide (NO) plays an essential role in the inhibitory neurotransmission of the bladder neck of several species, the current study investigates the mechanisms underlying the NO-induced relaxations in the pig urinary bladder neck. EXPERIMENTAL APPROACH: Urothelium-denuded bladder neck strips were dissected and mounted in isolated organ baths containing a physiological saline solution at 37 degrees C and continuously gassed with 5% CO(2) and 95% O(2), for isometric force recording. The relaxations to transmural nerve stimulation (EFS), or to exogenously applied acidified NaNO(2) solution were carried out on strips pre-contracted with phenylephrine, and treated with guanethidine and atropine, to block noradrenergic neurotransmission and muscarinic receptors, respectively. KEY RESULTS: EFS (0.2-1 Hz) and addition of acidified NaNO(2) solution (1 microM-1 mM) evoked frequency- and concentration-dependent relaxations, respectively. These responses were potently reduced by the blockade of guanylate cyclase and were not modified by the K(+) channel blockers iberiotoxin, charybdotoxin, apamin or glibenclamide. The voltage-gated K(+) (Kv) channels inhibitor 4-aminopyridine, greatly enhanced the nitrergic relaxations evoked by EFS, but did not affect the NaNO(2) solution-induced relaxations. CONCLUSIONS AND IMPLICATIONS: NO, whose release is modulated by pre-junctional Kv channels, relaxes the pig urinary bladder neck through a mechanism dependent on the activation of guanylate cyclase, in which post-junctional K(+) channels do not seem to be involved. Modulation of Kv channels could be useful in the therapy of the urinary incontinence produced by intrinsic sphincteric deficiency.

Ability of a Generalist Seed Beetle to Colonize an Exotic Host: Effects of Host Plant Origin and Oviposition Host.

The colonization of an exotic species by native herbivores is more likely to occur if that herbivore is a generalist. There is little information on the life-history mechanisms used by native generalist insects to colonize exotic hosts and how these mechanisms are affected by host properties. We examined the ability of the generalist seed beetle Stator limbatus Horn to colonize an exotic species. We compared its host preference, acceptability, performance, and egg size when ovipositing and developing on two native (Pithecellobium dulce (Roxb.) Benth and Senegalia riparia (Kunth)) and one exotic legume species (Leucaena leucocephala (Lam.)). We also analyzed the seed chemistry. We found that females recognize the exotic species as an unfavorable host for larval development and that they delayed oviposition and laid fewer and larger eggs on the exotic species than on the native species. Survivorship on the exotic host was 0%. Additionally, seeds of the native species contain five chemical compounds that are absent in the exotic species, and the exotic species contains three sterols, which are absent in the native legumes. Genetically based differences between beetles adapted to different hosts, plastic responses toward new hosts, and chemical differences among seeds are important in host colonization and recognition of the exotic host. In conclusion, the generalist nature of S. limbatus does not influence its ability to colonize L. leucocephala. Explanations for the colonization of exotic hosts by generalist native species and for the success of invasive species must be complemented with studies measuring local adaptation and plasticity.

Utilidad diagnóstica del dímero-D en el tromboembolismo pulmonar de pacientes COVID-19 / DiagnosticutilityofD-dimerin pulmonarythromboembolism in COVID-19 patients

Resumen Introducción: El aumento de la concentración de dímero-D en pacientes COVID-19 se ha asociado a mayor gravedad y peor pronóstico; sin embargo, su rol en predecir el diagnóstico de tromboembolismo pulmonar (TEP), aún es incierto. Objetivo: Evaluar la utilidad del dímero-D plasmático en el diagnóstico de TEP en pacientes con COVID-19. Pacientes y Métodos: Estudio observacional analítico. Se incluyó a pacientes COVID-19 que tenían una angiotomografía computada de tórax (AngioTAC). Se registraron datos clínicos, niveles plasmáticos de dímero-D de ingreso y previo al momento de realizar la AngioTAC. Se identificó la presencia o ausencia de TEP. Resultados: Se incluyeron 163 pacientes; 37(23%) presentaron TEP. Al comparar la serie de pacientes con TEP versus sin TEP, no se encontraron diferencias significativas en características clínicas, ni mortalidad. Hubo diferencias significativas en el nivel plasmático del dímero-D previo a realizar la AngioTAC (3.929 versus 1.912 μg/L; p = 0,005). El área bajo la curva ROC del dímero-D para TEPfue de 0,65. El mejor punto de corte del dímero-D fue de 2.000 μg/L, con una baja sensibilidad y valor predictivo positivo. El valor de corte con el mejor valor predictivo negativo (VPN)fue de 900 μg/L (96%), el cual fue mejor que la estrategia de corte de dímero D ajustado por edad (VPN 90%). Conclusión: La capacidad discriminativa del dímero D para diagnosticar TEP fue baja. En cambio, el dímero D mantiene un alto valor predictivo negativo para descartar TEP, el cual es mayor al valor descrito clásicamente en los pacientes no COVID.

Introduction: Increased D-dimer concentration in COVID-19 patients has been associated with greater severity and worse prognosis; however its role in predicting the diagnosis of pulmonary thromboembolism (PTE), is still uncertain. Objective: To evaluate the usefulness of plasma D-dimer in the diagnosis of PTE in patients with COVID-19. Method: Analytical observational study. COVID-19 patients who had a chest computed tomography angiography (CTA) were included. Clinical data, Ddimer plasma levels on admission and prior to CTA were recorded. The presence or absence of PTE was identified. Results: 163 patients were included, 37 (23%) presented PTE. After comparing the series of patients with PTE versus the series without PTE, no significant differences were found in clinical characteristics or mortality. There were significant differences in the plasma level of D-dimer prior to performing CTA (3,929 μg/L versus. 1,912 μg/L; p = 0.005). The area under the D-dimer ROC curve for PTEprediction was 0.65. The best D-dimer cutoffpoint was 2.000μg/L, with a low sensitivity and positivepredictive value. The cutoff value with the best negativepredictive value (NPV) was 900 μg/L (96%), which was better than the age-adjusted D-dimer cutoff strategy (NPV 90%). Conclusion: The discriminative ability of D-dimer to diagnose PTE was low. In contrast, D-dimer maintains a high negative predictive value to rule out PTE, which is higher than the value classically described in non-COVID patients.

Clinical practice guideline for the prevention, early detection, diagnosis, management and follow up of type 2 diabetes mellitus in adults.

In Colombia, diabetes mellitus is a public health program for those responsible for creating and implementing strategies for prevention, diagnosis, treatment, and follow-up that are applicable at all care levels, with the objective of establishing early and sustained control of diabetes. A clinical practice guide has been developed following the broad outline of the methodological guide from the Ministry of Health and Social Welfare, with the aim of systematically gathering scientific evidence and formulating recommendations using the GRADE (Grading of Recommendations Assessment, Development and Evaluation) methodology. The current document presents in summary form the results of this process, including the recommendations and the considerations taken into account in formulating them. In general terms, what is proposed here is a screening process using the Finnish Diabetes Risk Score questionnaire adapted to the Colombian population, which enables early diagnosis of the illness, and an algorithm for determining initial treatment that can be generalized to most patients with diabetes mellitus type 2 and that is simple to apply in a primary care context. In addition, several recommendations have been made to scale up pharmacological treatment in those patients that do not achieve the objectives or fail to maintain them during initial treatment. These recommendations also take into account the evolution of weight and the individualization of glycemic control goals for special populations. Finally, recommendations have been made for opportune detection of micro- and macrovascular complications of diabetes.

En Colombia la Diabetes Mellitus es un problema de salud pública por lo que deben generarse e implementarse estrategias de prevención, diagnóstico, tratamiento y seguimiento, aplicables en todos los niveles de atención con miras a establecer el control de la diabetes en forma temprana y sostenida. Se elaboró una guía de práctica clínica siguiendo los lineamientos de la guía metodológica del Ministerio de Salud y Protección Social para recolectar de forma sistemática la evidencia científica y formular las recomendaciones utilizando la metodología GRADE. El presente documento muestra, de forma resumida, el resultado de ese proceso, incluyendo las recomendaciones y las consideraciones tenidas en cuenta para llegar a ellas. En términos generales, se propone un proceso de tamización mediante el cuestionario FINDRISC adaptado a población Colombiana que permite llegar a un diagnóstico temprano de la enfermedad y un algoritmo para el manejo inicial que es generalizable a la gran mayoría de los pacientes con diabetes mellitus tipo 2 y que es sencillo de aplicar en atención primaria. También se hacen unas recomendaciones para escalar el tratamiento farmacológico de los pacientes que no alcanzan la meta o la pierden con el manejo inicial, teniendo en cuenta principalmente la evolución del peso y la individualización de la meta de control glucémico en poblaciones especiales. Finalmente se proponen algunas recomendaciones para la detección oportuna de las complicaciones micro y macrovasculares de la diabetes.

Time- and dose-dependency of intestinal lactase activity in adult rat on starch intake.

Although it is generally accepted that lactase (beta-D-galactosidase, EC 3.2.1.23) activity is not influenced by intake of saccharides containing alpha-linkages, an effect of these carbohydrates on lactase activity was never thoroughly investigated. Activity of lactase and sucrose alpha-D-glucohydrolase, EC 3.2.1 48) was determined in proximal, middle and distal thirds of the jejunoileum of female, 12-week-old rats, fed for 2 weeks a low-starch (5 cal%), high-fat (73%) diet, and in rats, that after this introduction period were fed for 1, 2 and 3 days, an isocaloric middle-starch (40%), middle-fat (36%) diet or an isocaloric high-starch (70%), low-fat (7%) diet. During the entire experimental period, the body weight changes, food intake and the amount of protein per segment were practically the same in all three dietary groups. In all intestinal segments, increased intake of starch was followed by an increase of lactase and sucroase activity (both expressed as per tissue protein or per intestinal segment ) within the first day. The increase continued during the second day and leveled off during the third day. A highly significant linear correlation was found between the search content of the diets and the lactase activity in all three segments. A highly significant correlation was also established in all three segments between sucrase and lactase activities. These studies thus demonstrated a dose- and time-dependency between the intake of starch (a carbohydrate containing only alpha-linkages) and the activity of lactase, a neutral beta-galactosidase in adult rats.

Dietary regulation of intestinal glucohydrolases in adult rats: comparison of the effect of solid and liquid diets containing glucose polymers, starch, or sucrose.

For 1 wk, 3-mo-old male rats were fed a low-starch (5 cal%), high-fat (73 cal%, corn oil) diet followed by a high-glucose-polymer (70 cal%), low-fat (7 cal%, corn oil) or a middle-glucose-polymer (40 cal%), middle-fat (37 cal%, corn oil) diet. Other animals were fed similar diets but with starch or sucrose instead of the glucose polymers. Rats were sacrificed 2 or 7 days later. Food intake, body weight changes, and protein content per intestinal segment were similar in all groups. Increased carbohydrate intake evoked an increase of sucrase, maltase, glucoamylase, and lactase activity in both the jejunum and ileum. Effect of glucose polymers on glucohydrolase was similar in animals fed commercial liquid-soy-based infant formulas containing sucrose, glucose polymers, or both. Results support using glucose polymers as replacements for sucrose or starch when digestion impairment of those sugars is suspected or when a formula of lower osmolality is indicated.

A2B adenosine receptors mediate relaxation of the pig intravesical ureter: adenosine modulation of non adrenergic non cholinergic excitatory neurotransmission.

1. The present study was designed to characterize the adenosine receptors involved in the relaxation of the pig intravesical ureter, and to investigate the action of adenosine on the non adrenergic non cholinergic (NANC) excitatory ureteral neurotransmission. 2. In U46619 (10(-7) M)-contracted strips treated with the adenosine uptake inhibitor, nitrobenzylthioinosine (NBTI, 10(-6) M), adenosine and related analogues induced relaxations with the following potency order: 5'-N-ethylcarboxamidoadenosine (NECA) = 5'-(N-cyclopropyl)-carboxamidoadenosine (CPCA) = 2-chloroadenosine (2-CA) > adenosine > cyclopentyladenosine (CPA) = N6-(3-iodobenzyl)-adenosine-5'-N-methylcarboxamide (IB-MECA) = 2-[p-(carboxyethyl)-phenylethylamino]-5'-N-ethylcarboxamidoaden os ine (CGS21680). 3. Epithelium removal or incubation with indomethacin (3 x 10(-6) M) and L-N(G)-nitroarginine (L-NOARG, 3 x 10(-5) M), inhibitors of prostanoids and nitric oxide (NO) synthase, respectively, failed to modify the relaxations to adenosine. 4. 1,3-dipropyl-8-cyclopentylxanthine (DPCPX, 10(-8) M) and 4-(2-[7-amino-2-(2-furyl) [1,2,4]-triazolo[2,3-a][1,3,5]triazin-5-ylamino]ethyl)phenol (ZM 241385, 3 x 10(-8) M and 10(-7) M), A1 and A2A receptor selective antagonists, respectively, did not modify the relaxations to adenosine or NECA. 8-phenyltheophylline (8-PT, 10(-5) M) and DPCPX (10(-6) M), which block A1/A2-receptors, reduced such relaxations. 5. In strips treated with guanethidine (10(-5) M), atropine (10(-7) M), L-NOARG (3 x 10(-5) M) and indomethacin (3 x 10(-6) M), both electrical field stimulation (EFS, 5 Hz) and exogenous ATP (10(-4) M) induced contractions of preparations. 8-PT (10(-5) M) increased both contractions. DPCPX (10(-8) M), NECA (10(-4) M), CPCA, (10(-4) M) and 2-CA (10(-4) M) did not alter the contractions to EFS. 6. The present results suggest that adenosine relaxes the pig intravesical ureter, independently of prostanoids or NO, through activation of A2B-receptors located in the smooth muscle. This relaxation may modulate the ureteral NANC excitatory neurotransmission through a postsynaptic mechanism.

Regression of diffuse intralobular liver fibrosis associated with visceral leishmaniasis.

Diffuse intralobular fibrosis of the liver is rare in cases of New World visceral leishmaniasis. A patient with this disease from a newly endemic area in the northernmost area of the Brazilian Amazon region was studied. Hypertrophy and hyperplasia of the phagocytic mononuclear cell system were observed, with parasitism and Disse's space fibrosis diffusely involving the liver. This description is based on a biopsy carried out after seven days of treatment with Glucantime. Another biopsy performed almost two years later showed no fibrosis, no Kupffer cell hypertrophy and hyperplasia, and no parasitism. The mechanism of fibrosis and regression is discussed.

Population study of horizontal cells in live carp retinas using microinjections of horseradish peroxidase.

In order to randomly sample horizontal cells (HCs) of carp retina, horseradish peroxidase (HRP) was delivered into axon terminals by means of vitreally inserted micropipettes in live fish. Survival time was extended to several hours to permit label diffusion into HC somata. A function measuring the relative complexity of cell contours was defined in order to help classify HCs according to their morphological types. The histogram of measurement from 313 HCs showed three modes fitting normal distributions. The numbers of cells in each group were 267, 36 and 10, respectively, representing a relative population of 85.3% H1s, 11.5% H2s and 3.2% H3s. It is suggested that cone HC somata are extended in a monolayer constituted by predominant type-H1 with interspersed groups of both type-H2 and type-H3 cells.

Fast activity and oscillatory potential of carp retina in the frequency domain.

There are two kinds of fast activity in the ERG: fast retinal potentials (FRP), an irregular series of spiky wavelets and oscillatory potentials (OP), a rhythmic sequence of events. Corneal ERG from nine intact young carps, evoked by extended pulses of diffuse white light under mesopic adaptation, displayed two different groups of wavelets related to ON and OFF, respectively. Stimulation and recording conditions were established to permit separate Fourier analysis of both groups of wavelets. Power distributions of normalized ON spectra showed both a wide dispersion and a high inter-subject variability. All normalized OFF spectra showed, instead, components within a narrow band from 52 to 56 Hz, most of them maximum relative power peaks. It is concluded that FRP originating in highly labile sources dominate ON fast activity, while the predominant OFF fast activity are OP originating in a stable discrete source.

Diet, age and intestinal bile acids in pigs.

Total bile acid concentrations in gallbladder bile and duodenal juice of neonatal piglets receiving sow milk were compared to values from 10-wk-old pigs receiving either high-fat low-carbohydrate (HF/LC) or low-fat high-carbohydrate (LF/HC) diets. Ten-week-old pigs on either diet had higher bile acid concentrations in gallbladder bile than newborn pigs (108.6 +/- 2.5 and 109.3 +/- 1.4 vs. 50.0 +/- 10.0 mM, mean +/- SE for HF/LC, LF/HC, and newborn, respectively, p < 0.007; n = 8-10). Ten-week-old pigs in the LF/HC group had higher bile acid concentrations in duodenal juice than either the HF/LC or newborn animals (31.7 +/- 4.2 vs. 16.8 +/- 2.5 and 14.7 +/- 1.8 mM, respectively, p < 0.0001). These data demonstrate that like the human neonate, the newborn pig has decreased bile acid concentrations available for digestion compared with the adult and resembles the adult pig adapted to a high-fat diet.

Body weight, static and dynamic skinfold thickness in small premature infants during the first month of life.

The growth of prematurely born infants is different from the growth of fetuses of the same age remaining in utero. This is in part due to changes in body composition that occur after birth. In search for a practical and reliable method to assess the growth of small prematures, we analyzed data obtained in two anthropometric studies that included 180 premature infants of 750-1750 g weight at birth, and we studied the relationships between weight, static skinfold thickness (SSFT) and dynamic skinfold thickness (delta SFT, i.e. the percentage of change in skinfold thickness between 15 and 60 s after application of the Harpenden caliper). The results show that the SSFT increases steadily after birth in spite of a significant decrease in weight and delta SFT. Whether it contains fat or not, the fold of the skin is increasing in thickness at a time when by weight alone, one would have considered that there was no growth. The nutritional implication of this finding remains to be studied. Serial correlations of measures obtained at each period indicate that weight and SSFT have a good correlation to same measures in subsequent weeks (P less than 0.01). delta SFT, however, showed only a weak correlation (P = 0.05). The delta SFT follows the general pattern of known changes in total body water, but it is not accurate enough to determine changes in individual infants; further studies are thus needed to find a practical method to evaluate changes of body composition and its relevance in the measurement of growth of premature infants.

Upper arm measurements of healthy neonates comparing ultrasonography and anthropometric methods.

OBJECTIVE: To compare measurements of the upper arm cross-sectional areas (total arm area, arm muscle area, and arm fat area of healthy neonates) as calculated using anthropometry with the values obtained by ultrasonography. MATERIALS AND METHODS: This study was performed on 60 consecutively born healthy neonates: gestational age (mean+/-SD) 39.6+/-1.2 weeks, birth weight 3287.1+/-307.7 g, 27 males (45%) and 33 females (55%). Mid-arm circumference and tricipital skinfold thickness measurements were taken on the left upper mid-arm according to the conventional anthropometric method to calculate total arm area, arm muscle area and arm fat area. The ultrasound evaluation was performed at the same arm location using a Toshiba sonolayer SSA-250A, which allows the calculation of the total arm area, arm muscle area and arm fat area by the number of pixels enclosed in the plotted areas. STATISTICAL ANALYSIS: whenever appropriate, parametric and non-parametric tests were used in order to compare measurements of paired samples and of groups of samples. RESULTS: No significant differences between males and females were found in any evaluated measurements, estimated either by anthropometry or by ultrasound. Also the median of total arm area did not differ significantly with either method (P = 0.337). Although there is evidence of concordance of the total arm area measurements (r = 0.68, 95% CI: 0.55-0.77) the two methods of measurement differed for arm muscle area and arm fat area. The estimated median of measurements by ultrasound for arm muscle area were significantly lower than those estimated by the anthropometric method, which differed by as much as 111% (P < 0.001). The estimated median ultrasound measurement of the arm fat was higher than the anthropometric arm fat area by as much as 31% (P < 0.001). CONCLUSION: Compared with ultrasound measurements using skinfold measurements and mid-arm circumference without further correction may lead to overestimation of the cross-sectional area of muscle and underestimation of the cross-sectional fat area. The correlation between the two methods could be interpreted as an indication for further search of correction factors in the equations.

Use of a transparent adhesive dressing in very low birthweight infants.

The present study was designed to test the safety and efficacy of a transparent adhesive dressing (TAD) to decrease transepidermal water loss (TEWL) in very low birthweight (VLBW) infants. Thirteen infants with birthweights of 770-1,450 g were randomly assigned to either routine care (n = 7) or TAD (n = 6). There were no differences between the groups with regard to weight at birth, length, head circumference, skinfold thickness measures, and fluid balance at any time during the study period. Electric current used by the radiant warmer operated in the servo-control mode was measured using a clamp-type AC ammeter connected to a single channel recorder. The TAD group used an average of 112 +/- 3.9 watts (n = 30 observation periods), the control group 133 +/- 5.5 (n = 34 observation periods), P = less than .01. TEWL measured by an evaporimeter in four infants of each group was significantly higher in the control group than it was in the TAD group in the area where the skin was covered.

Congenital mesoblastic nephroma.

Neonatal renal neoplasms are rare: most are congenital mesoblastic nephroma. In the past this neoplasm has been confused with Wilms' tumor, which in part may account for some of the more favorable prognosis ascribed to Wilms' tumor in children less than 1 yr of age. Congenital mesoblastic nephroma is usually a benign tumor. The recommended treatment is surgical excision. This is a report of two cases of congenital mesoblastic nephroma in infants who were treated successfully by nephrectomy.

Swelling of the leg, deep venous thrombosis and the piriformis syndrome.

BACKGROUND: The piriformis syndrome, which was first described 60 years ago, is a well recognized cause of sciatica, leg pain and low back pain, due to the entrapment of the sciatic nerve in the piriformis and other rotator muscles. Very few complications relating to this syndrome have been described. AIMS: To discuss how the piriformis syndrome may cause venous engorgement in the lower limb, and how the piriformis syndrome should be included as a possible cause of acute deep venous thrombosis in a not initially swollen leg. Both complications can occur independently. METHODS: Two cases of swelling of the leg and acute deep venous thrombosis independently associated with the piriformis syndrome are presented. CONCLUSIONS: Swelling of the leg and deep venous thrombosis are possible complications of the piriformis syndrome that occur due to entrapment of nerves and vessels within the leg, secondary to a severe spasm and hypertrophy of the piriformis and other rotator muscles.